Your stepbrother is a boy or man who became your brother because a parent of yours married a parent of his. He is the son of your stepmother or your stepfather, from their earlier relationship.

because因為 a parent of yours你的一位家長 married娶了或嫁了 a parent of his他的一位家長, your stepbrother你的繼兄弟 is是 a boy or man一個男孩或男人 who became your brother這樣才成了你的兄弟。He他 is是 the son of your stepmother or your stepfather你繼母或繼父的兒子, from their earlier relationship來自他們之前的一段感情。

The key point is that you share no blood: his mother or father is not yours, and yours is not his. You became family through the marriage.

The key point is重點是 that you share no blood你們沒有血緣關係: his mother or father他的爸爸媽媽 is not yours不是你的, and yours你的 is not his也不是他的。through the marriage因為這場婚姻, You became family你們才成為一家人。

This is different from a **half-brother**, who shares one parent with you by birth — for example, your father's son with a new wife. English keeps these two apart, and people do notice the difference.

This is different from a half-brother這跟「half-brother」（同父異母或同母異父的兄弟）不一樣, who shares one parent with you by birth他一出生就跟你有一位共同的親生父母 — for example舉例來說, your father's son with a new wife就像你爸爸跟新太太生的兒子。English英文 keeps these two apart把這兩個字分得很清楚, and people大家 do notice the difference也確實會注意到這個差別。

Whether someone actually says "stepbrother" in daily life depends on feeling, not grammar. Many people simply say "my brother" about a stepbrother they grew up with and love, and only say "stepbrother" when they need to explain the family history. Others use the word plainly with no bad feeling at all. It is not a rude word, but reaching for it can quietly signal distance, so listen to how each family talks.

in daily life在日常生活中, whether someone一個人到底會不會 actually says說出 "stepbrother"「stepbrother」這個字 depends on feeling靠的是感覺, not grammar不是文法規則。about a stepbrother they grew up with and love在講到一起長大、彼此有感情的繼兄弟時, many people很多人 simply say "my brother"就只說「my brother」, and when they need to explain the family history只有需要解釋家族背景時, they only say "stepbrother"才會說「stepbrother」。Others也有人 use the word plainly平常就直接使用這個字 with no bad feeling at all完全沒有負面的感覺。It is not a rude word這不是一個不禮貌的字, but不過 reaching for it如果特別去用它 can quietly signal distance可能會不知不覺透露出一點疏離感, so所以 listen to how each family talks要留意每個家庭實際上怎麼說。

Also note that "step-" here has nothing to do with walking. It is a much older word meaning a family joined after a loss.

Also另外要注意, note that "step-" here這裡的「step-」 has nothing to do with walking跟走路一點關係都沒有。It is a much older word這其實是一個歷史悠久很多的字, meaning意思是 a family joined after a loss因為失去親人而重新組成的家庭。